While wall forming systems have been in use for many years, a relatively recent development in this industry is in the use of polystyrene insulation panels as forms for the poured concrete walls. After the poured concrete within the forms has hardened, the insulation panels may be left in position on the walls to serve as permanent insulation, or they may be stripped off to reveal the exposed concrete.
Upon introduction of this new wall forming system, it was found that it was unnecessary to use small "building blocks" to create a system of form panels for the poured concrete. Rather, larger and larger panels are now being utilized to create the concrete forms. As the panels grew in size, the applicant herein devised several new types of ties, described in U.S. Pat. No. 4,765,109, which had special ends that could be "knocked off" to easily remove the large panels from the walls. While the patented tie has proven successful for its intended purpose, there are various instances where a different kind of tie would be more convenient and useful.
One problem with the previous tie design was in situations where a large 4'.times.8' panel was desired to be used as the forming structure. Because the original ties were designed to fit in slots in the upper or lower edges, it was not possible to insert a tie intermediate the edges of the panel.
Another problem with prior art forming systems was in the use of ties which would retain the insulation panel permanently on the wall. Such systems were not capable of use on those occasions where an exposed concrete surface is desired. In such instances, it was necessary to revert to the older methods of wooden forms which could be removed from the wall, but which left markings on the concrete wall which remained. While the applicant's previous tie design of U.S. Pat. No. 4,765,109 solved many of these problems in the use of its "knock off ends", those ties could not be utilized in any location other than the edges of the panel. Thus, it would be desirable to create a tie having removable and reusable end pieces for use in intermediate locations on the form panel.
A further problem in the prior art was in the use of wales to support the form panel system. Typically, such wales were bulky systems which had to be supported on their own against the wall, and which required a large number of ties and other materials to install and remove. Not only is the time loss considerable, but it is necessary to utilize a large number of materials and tools which must be carried by the construction crew from site to site.
The applicant devised two improvements to the original tie, which are described in U.S. Pat. Nos. 4,936,540 and 4,938,449. While these newer ties solved many of the problems with the prior art tie and forming system, they also had several drawbacks. First, the end tie plate used with the tie was relatively complicated and expensive to manufacture. Second, the portion of the tie designed to receive a wale did not have the ultimate strength desired for the desired uses. Finally, the protruding ends of the ties permitted undesirable twisting when placed under great stress from a wale.
It is therefore a general object of the present invention to provide an improved tie for use with conventional insulation panel type forms on poured concrete walls.
Another object of the present invention is to provide a tie which can be inserted through the intermediate portion of an insulation panel form to retain the form panel in position.
A further object is to provide a concrete wall form tie which has removable end pieces for retaining the panel in position.
Still another object of the present invention is to provide a concrete form panel tie which has reusable end pieces for retaining the panels in position.
Yet another object is to provide a form panel tie with ends designed to prevent twisting when placed under pressure from a wale.
Still another object of the present invention is to provide a tie with a reusable end piece which locks in position to retain the form panel in place.
These and other objects of the present invention will be apparent to those skilled in the art.